The paper deals with flow through rockfill to analyze the problem of flood routing through large masses of waste rock from mining operations dumped in natural channels. Rock dumps in ephemerous streams act as dams which retain incoming floods during intense rain storms. The paper describes a numerical model for flood routing through rock dumps in natural channels. The model was designed as a tool for predicting maximum water depth in a series of dumps separated by reaches of open channel as well as the peak outflow from each dump.